Methods and apparatus for disinfecting and reflux prevention flush syringe assembly

ABSTRACT

Embodiments of the invention are directed to flush syringe assemblies comprising an integrated contamination-prevention device integrated with device connector flushing positioned so that the practitioner cannot forget to apply disinfectant. The flush syringe assemblies comprise a barrel with an elongate plunger rod disposed therein and a cap comprising a passageway. The plunger rod includes a stopper of which at least a portion can be embedded in the passageway of the cap to form a plug in the cap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/689,095, filed Nov. 29, 2012, the entire disclosure of which ishereby incorporated by reference herein.

FIELD

Embodiments of the invention generally relate to apparatus and methodsto prevent blood reflux in vascular access devices (VAD). Morespecifically, embodiments of the invention are directed to technology toreduce the risk for bloodstream infections (CRBSI) and intravenous (IV)line patency maintenance including one or more of IV connectorscleaning, reflux prevention, connector capping technology, syringeassemblies and particularly to syringe assemblies for use in flushprocedures, for vascular access devices (VADs) such as peripheralcatheters and central venous catheters.

BACKGROUND

VADs are commonly used therapeutic devices yet accounted for 18,000blood stream infections in American ICUs in 2009, according to the CDC,which also reports a mortality rate of 12-25%. MMWR Morb. Mortal Wkly.Rep. 2011; 60:243-248. In the same article, the CDC attributesadditional blood stream infections and deaths to VAD use in regularhospital rooms and out-patient care.

If not properly maintained the VADs, which include peripheral cathetersand central venous catheters, can become sealed with blood clots orspread infection. To ensure VADs are used properly and do not becomesealed or infected, protocols have been developed. These protocolsinclude sterilizing the VAD and the flushing the catheter with a flushsolution. VAD protocols usually recommend flush procedures be performedafter catheter placement, before fluid infusion, and before and afterdrug administration, blood sampling, transfusions and parenteralnutrition. The goal of these flush procedures is to confirm catheterpatency, avoid drug incompatibilities, ensure the complete drug doseadministration, prevent thrombus formation and minimize the risk ofblood stream infections. Before each flush procedure is performed, theVAD should be sterilized. A recent study reported that 30% of the time,there is no effort to sterilize the VAD prior to flushing and when anattempt to sterilize the VAD it often did not fully meet asepticpractices.

Catheters are flushed using syringe assemblies filled with variousfluids. In some cases, different fluids are injected sequentially inaccordance with the protocol. For example, a saline solution followed byan anticoagulant such as heparin. The size of the syringe used to flushLV. lines varies by various factors including the size and length of thecatheter. Typically syringes of 1 ml, 3 ml, 5 ml and 10 ml volume areused.

It is important in the flush procedure not to draw blood back into thecatheter where it can clot and seal the catheter, commonly referred toas “reflux”. In order to prevent blood reflux into the catheter the useris encouraged to maintain a positive pressure in the line during theflush procedure. This may involve clamping the IV line and Withdrawingthe syringe and cannula from the LV. port while still applying pressureto the syringe plunger rod during the flush procedure. When using asyringe with an elastomeric stopper, the stopper is often compressedwhen it contacts the distal end of the syringe barrel at the completionof the flush procedure. When a user relieves the pressure to the plungerafter the flush procedure is completed, the stopper will expand back toits normal size thereby withdrawing liquid from the catheter into thesyringe barrel. This is undesirable, since it can cause blood to enterthe catheter at the catheter distal end (reflux) where it will remainstationary until the next time the VAD is used.

IV lines are now being flushed by a wide variety of health care workers,not just those who in the past were dedicated to catheter maintenance.In the case of out-patient care, the patients themselves may even flushtheir own catheters. These less experienced persons might prematurelyrelease the compressive force on the stopper or use excessive forcewhich would deform the stopper, either which may draw blood into thecatheter and cause reflux of blood. Consequently, there is a need forflush syringe assemblies which promote sterilizing the VAD and helpreduce or eliminate reflux of blood during the flushing procedure evenif flush protocols are not precisely followed.

SUMMARY

One or more embodiments of the invention are directed to flush syringeassemblies comprising a barrel, an elongate plunger rod, a cap, a sleeveand a disinfecting system. The barrel includes a side wall having aninside surface defining a chamber for retaining fluid, an outsidesurface, an open proximal end, a distal end including a distal wallhaving a passageway therethrough in fluid communication with thechamber. The elongate plunger rod is disposed within the barrel. Theplunger rod comprises a distal end including a stopper slidablypositioned in fluid-tight contact with the inside surface of the barrelfor driving fluid out of the chamber by movement of the stopper relativeto the barrel. The stopper comprises a stopper body and a detachablestopper tip. The cap comprises an outer wall surrounding a Luerconnection. The cap comprises a passageway for fluid communicationtherethrough, wherein the passageway is undercut to receive and retainthe stopper tip when the plunger rod is fully depressed. The cap furthercomprises a distal end for releasably attaching the cap to a vascularaccess device (VAD) and a proximal end for releasably attaching the capto the barrel. The sleeve is external to the barrel and has a distal endand a proximal end, and an inside surface and an outside surface. Thesleeve slides from distal to proximal positions in relationship to thebarrel. The disinfecting system comprises a disinfectant contained in ahub, wherein the disinfecting system is released upon proximal motion ofthe sleeve.

In some embodiments, the cap is threaded to engage complementary threadson the VAD. In one or more embodiments, the cap engages the VAD with aninterference fit. In certain embodiments, the passageway of the cap iscoated with an antimicrobial agent.

In some embodiments, the undercut of the passageway of the cap creates atight interference fit sufficient for retaining the stopper tip withinthe cap upon movement of the plunger rod away from the cap afteremptying the fluid from the syringe.

In one or more embodiments, the stopper tip has threads which engagewith complementary threads on the stopper body. In some embodiments, thestopper tip is secured to the stopper body using an interference fit. Indetailed embodiments, the stopper body is made of material selected fromthe list consisting of thermoplastic elastomers, natural rubber,synthetic rubber, thermoplastic materials and combinations thereof. Incertain embodiments, the stopper tip is made of material selected fromthe list consisting of thermoplastic elastomers, natural rubber,synthetic rubber, thermoplastic materials and combinations thereof.

In one or more embodiments, the outside surface of the barrel furthercomprises two annular positioning ridges, a distal annular positioningridge and a proximal annular positioning ridge. In some embodiments, theinside surface of the sleeve further comprises at least one annularpositioning groove for controlling the position of the sleeve relativeto the barrel by engaging with the annular positioning ridges on theoutside surface of the barrel. In detailed embodiments, the outsidesurface of the barrel comprises one or more ridges that extend along alength of the barrel and engage with the corresponding groove on theinside surface of the sleeve.

In some embodiments, the plunger is of sufficient length relative to thesleeve and the barrel that when plunger is fully depressed after allflushing solution has been expelled from the syringe, the sleeveretracts to expose the cap.

In some embodiments, the sleeve further comprises one or more cutouts toprovide visibility to the flush solution of the barrel. In one or moreembodiments, the distal end of the sleeve is threaded to engagecomplementary threads on the disinfecting system. In specificembodiments, the distal end of the sleeve is attached to thedisinfecting system using an interference fit.

In some embodiments, the disinfecting system further comprises aremovable cover to protect the disinfecting system prior to use and adisinfectant carrier. In one or more embodiments, the disinfectant ismade of material selected from the group consisting of: alcohol, anantiseptic gel, and combinations thereof.

Additional embodiments of the invention are directed to methods offlushing a VAD. A flush syringe assembly, as described herein, isprovided. The protective cover is removed using one hand from the distalend of the flush syringe assembly thereby exposing a disinfectantcontained at the distal end of the syringe assembly. The disinfectant isapplied to the VAD connector using one hand. The same hand ejects thedisinfecting system. The flush syringe assembly is coupled to the VAD.Using one hand, the flush syringe assembly is held and the plunger isdepressed to flush the VAD with a flush solution that is contained inthe chamber. Using the same hand to continue to depress the plungerafter the barrel is empty to embed the stopper tip into the VAD andretract the sleeve to expose the cap. The cap including the embeddedstopper tip is separated from the flush syringe assembly.

In some embodiments, the method further comprises removing the capincluding the embedded stopper tip and repeating the steps throughseparating the cap including the stopper tip from the flush syringeassembly.

Further embodiments of the invention are directed to flush syringeassemblies comprising a barrel, a cap, a releasable disinfecting system,an elongate plunger rod, a sleeve and a quantity of flush solution. Thebarrel includes a side wall having an inside surface defining a chamberfor retaining fluid, an outside surface, an open proximal end, a distalend including a distal wall with a tip extending distally therefromhaving a passageway therethrough in fluid communication with thechamber. The barrel further comprises an outside surface containing oneor more annular positioning discontinuity. The cap comprises a distalend and a proximal end defining a length, an irregularly shaped outerwall, a profiled center passageway providing fluid communication fromthe chamber to a patient's vascular access device (VAD). The cap furthercomprises a distal end annular channel that releasably attaches the capto the VAD, and a proximal end annular channel that releasably attachesthe cap to the barrel. The releasable disinfecting system comprises adisinfectant. The elongate plunger rod is disposed within the barrel andcomprises a distal portion and a proximal portion. The plunger rodfurther comprises a distal end including a stopper slidably positionedin fluid-tight contact with the barrel inside surface for expellingfluid from the chamber by movement of the stopper relative to thebarrel. The stopper has a distal face and a proximal end. The distalface of the stopper further comprises a profiled stopper tip that isdetachable from the stopper and seatable in the cap when the plunger rodis fully depressed. The sleeve is external to the barrel and has aninside surface and an outside surface, an open proximal end containingat least one flange, and an open distal end defining a recess with anirregular inner surface to contain and prevent rotation of the caprelative to the sleeve. The distal end is further connected to thereleasable disinfecting system. The sleeve further comprises one or moreannular positioning discontinuity complementary to the one or moreannular positioning discontinuity on the barrel, which together controldistal motion of the barrel relative to the sleeve. The quantity offlush solution is in the chamber between the stopper and distal wall ofthe barrel.

In some embodiments, the distal end annular channel of the cap furthercomprises a straight inner wall and an outer wall that is threaded tocomplement the VAD, and the distal end annular channel extends less thanthe length of the cap.

In one or more embodiments, the proximal end annular channel of the capfurther comprises a straight outer wall and an inner wall that isreleasably attached to the barrel, and the proximal end annular channelextends less than the length of the cap. In detailed embodiments, theproximal end annular channel of the cap is attached to the barrel by oneor more of an interference fit and a threaded connector.

In some embodiments, the profiled center passageway of the cap extendsthe entire length of the cap to establish fluid connection between thebarrel and the VAD, and the profile of the center passageway is undercutnear the proximal end to complement the profile of external surface ofstopper tip. In detailed embodiments, the profiled center passageway ofthe cap is coated with an antimicrobial agent.

In one or more embodiments, the stopper or any portion of the stopper isdetachable from the stopper and capable of being embedded into the VAD.In some embodiments, the stopper has a cavity to hold a stopper tip byone or more of a threaded connection and an interference fit. Indetailed embodiments, the profile of the distal end of the stopper tipis configured to complement the profile of the center passageway of thecap and create an interference fit therewith sufficient to retain thestopper tip within the VAD after the flush syringe assembly is removed.In specific embodiments, the stopper tip is threadably attached tostopper using threads on the stopper tip that complement those on theVAD allowing both to be removed in one motion by the practitioner.

In some embodiments, the annular positioning discontinuities on thebarrel comprise two annular positioning ridges, a distal annularpositioning ridge and a proximal annular positioning ridge and thediscontinuity on the sleeve comprises a groove configured to interactwith the annular positioning ridges on the barrel.

In one or more embodiments, the outside surface of the barrel furthercomprises one or more linear discontinuity spaced around the barrel thatrun along a length of the barrel and engage with a correspondingdiscontinuity on the inside surface of the sleeve.

Additional embodiments of the invention are directed to methods ofsterilizing a VAD connector prior to flushing. A protective cover isremoved from the distal end of the syringe assembly as described hereinto expose a disinfectant contained at the distal end of the syringeassembly. The disinfectant is applied to the VAD connector and thesleeve is depressed to eject the disinfecting system, or disinfectantcarrier and hub.

Further embodiments of the invention are directed to methods ofpreventing contamination of a VAD connector while being worn by apatient. The method comprising leaving a Luer cap containing an embeddedplunger tip connected to the VAD connector to protect the VAD connectorfrom contact with bacteria or other contaminants.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the inventionare attained and can be understood in detail, a more particulardescription of the invention, briefly summarized above, may be had byreference to the embodiments thereof which are illustrated in theappended drawings. It is to be noted, however, that the appendeddrawings illustrate only typical embodiments of this invention and aretherefore not to be considered limiting of its scope, for the inventionmay admit to other equally effective embodiments.

FIG. 1 shows a perspective view of a flush syringe assembly inaccordance with one or more embodiments of the invention;

FIG. 2 shows a perspective view of a syringe barrel in accordance withone or more embodiments of the invention;

FIG. 3 shows a cross-sectional side view of a syringe barrel inaccordance with one or more embodiments of the invention;

FIG. 4A shows a distal perspective view of a cap in accordance with oneor more embodiments of the invention;

FIG. 4B shows a proximal perspective view of a cap in accordance withone or more embodiments of the invention;

FIG. 5 shows a cross-sectional view of a cap in accordance with one ormore embodiments of the invention;

FIG. 6 shows a perspective view of a sleeve in accordance with one ormore embodiments of the invention;

FIG. 7 shows a cross-sectional view of a sleeve in accordance with oneor more embodiments of the invention;

FIG. 8 shows a distal perspective view of a stopper in accordance withone or more embodiments of the invention;

FIG. 9 shows a cross-sectional view of a stopper in accordance with oneor more embodiments of the invention;

FIG. 10 shows a distal perspective view of a detachable stopper tip inaccordance with one or more embodiments of the invention;

FIG. 11 shows a cross-sectional view of a detachable stopper tip inaccordance with one or more embodiments of the invention;

FIG. 12 shows a perspective view of a flush syringe assembly inaccordance with one or more embodiments of the invention;

FIG. 13 shows a cross-sectional view of a flush syringe assembly inaccordance with one or more embodiments of the invention;

FIG. 14 shows a perspective view of a flush syringe assembly and a VADprior to cleaning the VAD in accordance with one or more embodiments ofthe invention;

FIG. 15 shows an expanded cross-sectional view of a flush syringeassembly and a VAD prior to cleaning the VAD in accordance with one ormore embodiments of the invention;

FIG. 16 shows a cross-sectional view of a flush syringe assemblycleaning a VAD in accordance with one or more embodiments of theinvention;

FIG. 17 shows an expanded cross-sectional view of the flush syringeassembly cleaning a VAD in accordance with one or more embodiments ofthe invention;

FIG. 18 shows a cross-sectional view of a flush syringe assembly afterretracting the sleeve to disengage the disinfecting system in accordancewith one or more embodiments of the invention;

FIG. 19 shows an expanded cross-sectional view of the flush syringeassembly and the disinfecting system after disengagement in accordancewith one or more embodiments of the invention;

FIG. 20 shows an expanded cross-sectional view of a stopper anddetachable stopper tip in accordance with one or more embodiments of theinvention;

FIG. 21 shows a cross-sectional view of a VAD being connected to theflush syringe assembly in accordance with one or more embodiments of theinvention;

FIG. 22 shows an expanded cross-sectional view of the VAD connected tothe flush syringe assembly in accordance with one or more embodiments ofthe invention;

FIG. 23 shows a cross-sectional view of the flush syringe assemblyconnected to the VAD in the initial position in accordance with one ormore embodiments of the invention;

FIG. 24 shows a cross-sectional view of the flush syringe assemblyconnected to the VAD during flushing in accordance with one or moreembodiments of the invention;

FIG. 25 shows a cross-sectional view of the flush syringe assemblyconnected to the VAD after flushing in accordance with one or moreembodiments of the invention;

FIG. 26 shows an expanded cross-sectional view of the flush syringeassembly connected to the VAD after flushing with the stopper tipengaged with the cap in accordance with one or more embodiments of theinvention;

FIG. 27 shows a cross-sectional view of the flush syringe assemblyconnected to the VAD after flushing during the initial withdrawal stagewith the cap exposed in accordance with one or more embodiments of theinvention;

FIG. 28 shows an expanded cross-sectional view of the flush syringeassembly connected to the VAD after flushing with the cap exposed fromunder the sleeve in accordance with one or more embodiments of theinvention;

FIG. 29 shows an expanded cross-sectional view of the plunger rod,sleeve and barrel during removal in accordance with one or moreembodiments of the invention;

FIG. 30 shows a perspective view of the flush syringe assembly with thesleeve retracted being removed from the VAD leaving the cap and stoppertip in the VAD in accordance with one or more embodiments of theinvention;

FIG. 31 shows a cross-sectional view of the flush syringe assembly andVAD after disconnection in accordance with one or more embodiments ofthe invention; and

FIG. 32 shows an expanded cross-sectional view of the VAD with the capand stopper tip embedded in the cap in accordance with one or moreembodiments of the invention.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the invention, it isto be understood that the invention is not limited to the details ofconstruction or process steps set forth in the following description.The invention is capable of other embodiments and of being practiced orbeing carried out in various ways.

Embodiments of the invention are directed to syringe assemblies withvalves and plugs which allow for one or more of prevention of bloodreflux, elimination of the need for catheter positive displacementconnectors and protection of the IV connector by capping of the IVconnector.

The devices may prevent blood reflux into IV catheter lumens, after thecatheter flushing procedure, eliminate the need for IV catheter positivedisplacement connectors or valves and/or protect the IV connector fromcontamination by capping the IV connector. These systems have thepotential to extend catheter dwell times, reduce the use of Cathflo®(t-PA, Alteplase), and cap IV connectors to reduce the risk forconnector inlet port bacterial colonization. One or more embodiments aredirected to systems for disinfecting/cleaning connectors, flushing IVlines, preventing reflux, capping/sealing connector inlet port surfaces(e.g., to prevent microorganisms from entering IV lines or populate theconnector inlet port surfaces).

The figures show embodiments of a syringe assembly comprising anintegrated contamination-prevention device integrated with VAD connectorflushing positioned so that the practitioner cannot forget to applydisinfectant. Those skilled in the art will understand that the syringeassembly shown is merely one embodiment and that the syringe assemblycan have different structures and components. Accordingly, one or moreembodiments of the invention are directed to flush syringe assemblies100 including a barrel 110, an elongate plunger rod 120, a cap 130 and avalve 140.

Referring to FIGS. 2 and 3, the barrel 110 has a side wall 111 with aninside surface 112 defining a chamber 114 for retaining a fluid, anoutside surface 113, an open proximal end 115 and a distal end 116. Thedistal end 116 includes a distal wall 117 with an passageway 118therethrough in fluid communication with the chamber 114 allowing afluid within the chamber 114 to exit the chamber through the passageway118. In some embodiments, the barrel 110 does not include a flange forproviding opposing force to the direction of movement of the plungerrod.

The outside surface 113 of the barrel 110 can be smooth or textureddepending on the desired frictional quality of the resulting syringeassembly 100. For example, a textured outside surface 113 may offer theuser a more stable and secure grip than a smooth surface. Additionally,the roughness or frictional feel of the outside surface 113 may bemodified by the chemical composition of the material used in the syringebarrel 110.

The barrel 110 may also include features to control the linear movementof the barrel relative to a sleeve and to restrict their relativerotational movement. To control the linear movement of the barrel 110relative to the sleeve, the barrel may include at least one annularpositioning ridge 167, 168 on the outside surface. In the embodimentshown in FIG. 1, the barrel includes a proximal annular positioningridge 168 and a distal annular positioning ridge 167. To control thelinear movement, in some embodiments, annular ridges 167, 168 can engagewith corresponding features on the inside surface of the sleeve. In someembodiments, the distal annular positioning ridge 167 positions thesleeve 160 during shipping of the flush syringe assembly. In one or moreembodiments the proximal annular positioning ridge 168 stops themovement of the sleeve 160 relative to the barrel 110 after thedisinfecting system is ejected.

To control the rotational movement of the sleeve 160 relative to thebarrel 110, the barrel may contain a ridge 167 that can extend, forexample, substantially from the proximal end 115 of the barrel 110toward the distal end 116. The ridge 167 can extend along any portion ofthe length of the barrel 110. The ridges 138 can start and stop at anypoint along the length of the barrel 110. The ridges 138 (or ridge) canbe sized to engage with a corresponding groove 177 on the inside surface163 of a sleeve 160 to facilitate alignment of the barrel 110 with thesleeve 160 while the plunger is being depressed.

While the embodiments have been described and shown as having a ridgeextending from the barrel to interact with a groove in the sleeve, itwill be understood by those skilled in the art that these features canbe reversed. For example, there may be a least one annular positioninggroove on the barrel that interacts with at least one annularpositioning ridge on the inside surface of the sleeve. In someembodiments, there are at least one annular positioning discontinuity onthe barrel and at least one complementary annular positioningdiscontinuity on the inside surface of the sleeve. Similarly, the barrelmay contain a linear discontinuity that extends along a length of thebarrel that interacts with a complementary discontinuity on the insidesurface of the sleeve.

The barrel 110 may also include a tip 119 which extends distally fromthe barrel 110. The tip 119 can have an outer diameter that is differentfrom or the same as the outer diameter of the rest of the barrel 110.For example, as shown in the Figures, the outer diameter of the tip 119has a smaller outer diameter than the barrel portion that is proximal ofthe tip 119. The tip 119 of the barrel 110 may include a Luer slipconnection (not shown) or a locking Luer type collar concentricallysurrounding the tip 119 or within the tip. The tip 119 shown in theFigures is a Luer lock type connector 127 on the inside of the tip.

An elongate plunger rod 120 is disposed within the barrel 110, as shownin FIGS. 1 and 8 to 9. The plunger rod 120 includes an elongate bodyportion 121 with a proximal end 122 and a distal end 123.

The elongate body portion 121 of the plunger rod 120 has an axial lengthextending from the proximal end 122 to the distal end 123. The bodyportion 121 may include a single beam or features, which may havecylindrical or other shapes. As shown in the Figures, the body portion121 is formed by two perpendicularly intersecting beams 124, 125. Thebeams may have a plus-shaped or cruciform cross-section. In theembodiment shown, the two intersecting beams 124, 125 intersect to forman outside surface outlining four quadrants that face the inside surface112 of the barrel 110 and extend along the axial length from theproximal end 122 to the distal end 123 of the plunger rod 120. While thedrawings show embodiments of the plunger rod with a cruciformcross-section, it will be understood by those skilled in the art thatthe shape and/or cross-section of the plunger rod can be any suitableshape or cross-section and that the embodiments of the invention are notlimited to the shapes shown in the drawings.

The plunger rod 120 may also include a thumbpress 126 at the proximalend 122 of the elongate body portion 121. The shape of the thumbpress126 can vary depending on the desired usage of the flush syringeassembly 100. The thumbpress 126 shown in the drawings is round, but itwill be understood by those skilled in the art that this is merelyrepresentative of one possible shape. Other shapes include, but are notlimited to, square, rectangular, triangular, oval, pentagonal, hexagonaland cruciform. The shape of the thumbpress 126 in some embodimentssubstantially matches the shape of the elongate body portion 121 of theplunger rod 120, the barrel 110 or other components.

In some embodiments, the thumbpress has a plurality of ridges 127thereon. The ridges 127 may enhance the ability of the user to press theplunger rod 120 distally with respect to the barrel 110 by providing asurface with an increased coefficient of friction. The shape of theridges 127 or the ridge pattern can be changed depending on the desiredusage of the plunger rod 120. For example, the ridges 127 can be aseries of parallel lines, or curved in a design. In one or moreembodiments, the ridges 127 are shaped to form a logo. The ridges 127can be integrally formed with the plunger rod 120 or can be separatepieces that are attached to the plunger rod. The surface of the ridges127 can be textured differently from the plunger rod or can be the same.Ridges 127 with a textured surface may provide a greater increase in thecoefficient of friction than smooth ridges.

A stopper 150 can be connected to the distal end 123 of the plunger rod120. The shape and size of the stopper 150 can be any suitable shape orsize depending on, for example, the shape and size of the barrel 110 andplunger rod 120. The plunger rod 120 is slidably positioned in thebarrel 110 so that the stopper 150 is in fluid-tight contact with theinside surface 112 of the barrel 110 and so that distal movement of theplunger rod 120 relative to the barrel 110 causes the stopper 150 topush the fluid out of the barrel 110. In some embodiments, the stopper150 is slidably positioned in fluid-tight contact with the insidesurface 112 of the barrel 110 for driving fluid out of the chamber 114by movement of the stopper 150 relative to the barrel 110.

The plunger rod 120 shown in FIG. 1 includes a connector 128 on thedistal end 123 of the plunger rod 120. The connector 128 shown includesscrew threads 129 to which a stopper 150, or other component, can beattached by cooperative interaction with screw threads on the stopper150. It will be understood by those skilled in the art that there areother types of connectors 128 besides screw threads 129. For example,the connector may include one or more axially spaced rings about theoutside surface of the connector 128. The spaced rings provide cancooperatively interact with one or more grooves in the stopper 150 toaffix the stopper 150 to the distal end 123 of the plunger rod 120.

The stopper 150 can be connected to the distal end 123 of the elongateplunger rod 120 by any suitable means. In some embodiments, the stopper150 is connected by a mechanical connection such as interaction ofcomplementary screw threads, as shown in FIG. 9, and press-fitconnections. The stopper 150 can be a single piece or multiple pieces.In some embodiments, the stopper 150 is multiple pieces having a stopperbody 151 and a detachable stopper tip 155, as shown in FIGS. 1, 10 and11. In one or more embodiments, the stopper 150 includes aconically-shaped distal surface 152 and the barrel 110 includes aconically-shaped inside surface at the distal wall 117. Those skilled inthe art will understand that conically-shaped can also includefrustoconical shapes. In some embodiments, the stopper 150 includes ashape that is complementary to the shape of the distal end of the barrel110 so that the stopper 150 is effective to expel the contents of thechamber 114 through the distal end 116 of the barrel 110. The stopper150 may be slidably positioned in fluid-tight engagement with the insidesurface 112 of the barrel 110 for drawing fluid into and driving fluidout of the chamber 114. If the syringe assembly is prefilled from themanufacturer, the stopper 150 need not be used for or able to draw fluidinto the barrel 110.

The stopper 150 may be made of any material suitable for providing aseal with the inside surface 112 of the barrel 110. For example, thestopper 150 may be made of thermoplastic elastomers, natural rubber,synthetic rubber or thermoplastic materials and combinations thereof.The stopper 150 may be integrally formed or composed of separatecomponents of the same or different materials joined together. Theplunger rod 120 may be made of material which is more rigid than thestopper 150 such as polypropylene, polyethylene and the like. Materialsshould be chosen to be compatible with the procedure being used.

As shown in FIGS. 8 and 9, the stopper may include a cavity 153 in thedistal end to allow a detachable stopper tip 155 to be connectedthereto. The detachable stopper tip 155 can be connected to the stopper150 by any suitable connection including, but not limited to, screwthreads or a interference fit. The stopper 150 shown in FIGS. 8 and 9includes screw threads 154 in the cavity 153 which can cooperativelyinteract with the detachable stopper tip 155.

As shown in FIGS. 10 and 11, the detachable stopper tip 155 includes abody 156 with a proximal end 157 and distal end 158. The proximal end157 of the tip 155 shown in the Figures includes screw threads 159 whichcan interact with the complementary threads on the stopper 150. It willbe understood by those skilled in the art that the cooperative nature ofthe screw threads hold the detachable stopper tip 155 to the stopper 150during normal use and can be overcome to release the detachable stoppertip 155 from the stopper 150 when needed, as described further below.

The distal end 158 of the detachable stopper tip 155 can be any suitableshape. For example, as shown in FIG. 11, the distal end 158 of the tip155 can be shaped like a tow hitch with a region of smaller diameter toform a tight connection with a mating surface. As described furtherbelow, in use, the larger diameter end of the tip 155 passes into theVAD, or other connection and becomes wedged in place by the smallerdiameter portion, so that upon retraction of the stopper, the screwthreads of the tip are overcome, releasing the tip from the stopper andleaving the tip wedged in the VAD.

In some embodiments, the distal end 158 of the detachable stopper tip155 comprises a profiled tip. The profiled tip can be sized and shapedto be seatable within the VAD when the plunger rod is fully depressed.For example, the detachable stopper tip can be seated in acorrespondingly shaped undercut region 192 in the cap 130 which can thenbe left on the end of the vascular access device, thereby sealing theVAD with the combined cap 130 and detachable stopper tip 155. Thedetachable stopper tip 155 with the profiled distal end 158 isconfigured to complement the profile of the center passageway 134 of thecap 130 to create an interference fit therewith sufficient to retain thedetachable stopper tip within the VAD after the flush syringe assembly100 has been removed. For example, the center passageway 134 may includethe undercut region 192 described with reference to FIG. 5.

In one or more embodiments, the stopper 150 or a portion of the stopper(e.g., the detachable stopper tip 155) can be detached from the stopper150 or from the plunger rod 120 and can be embedded into the VAD, orinto a suitable undercut region 192 in the cap 130.

The cap 130 of various embodiments includes a body 131 with a proximalend 132, a distal end 133 and a tip 136 extending distally from thedistal end 133. The distal end 133 and the proximal end 132 define thelength of the cap 130. FIGS. 4A, 4B and 5 show a distal view, a proximalview and a cross-sectional view, respectively, of a cap 130 inaccordance with one or more embodiments of the invention. Upon assembly,the proximal end 132 of the cap 130 is adjacent the distal end 116 ofthe barrel 110. The cap 130 comprises a passageway 134 extending throughthe tip 136 and the body 131 of the cap 130. The passageway 134 allowsfor fluid communication between the chamber 114 of the barrel 110 andthe device attached to the distal end 133 of the cap 130. Thus allowinga fluid within the chamber 114 to be expelled through the distal end ofthe barrel 110 and through the cap 130 from the distal end 133 to theproximal end 132.

The cross-sectional shape of the cap 130 can be any suitable shapeincluding, but not limited to, triangular, square, pentagonal,hexagonal, heptagonal, octagonal, symmetric or non-symmetric polygonal.The shape of the cap 130 can provide a comfortable feel for the user andenhanced gripping ability to allow the user to easily connect ordisconnect the cap from the barrel 110. In some embodiments, the cap 130is irregularly shaped. As used in this specification and the appendedclaims, the term “irregularly shaped” means that the cross-sectionalshape provides a surface or edge that is detrimental to free rotationabout the cross-section. For example, a hexagon or oval shape would beconsidered “irregular”.

As shown in FIG. 5, the distal end of the passageway 134 can be profiledto cooperatively interact with a detachable stopper tip to form a seal.This profiled area may be referred to as an undercut region 192, but itwill be understood by those skilled in the art that the profile is notlimited to undercut profiles. In some embodiments, the profiled centerpassageway of the cap 130 extends the entire length of the cap 130 toestablish fluid connection between the barrel 110 and the VAD and theprofile of the center passageway is undercut near the proximal end tocomplement the profile of an external surface of the stopper tip or thedetachable stopper tip.

The cap 130 includes a Luer connector 135 on the distal end 133, asshown in FIGS. 4A and 5. The Luer connector 135 allows the cap 130, andany connected barrel 110, to be releasably connectable to a vascularaccess device (VAD) or other suitable device with a matching Luer typeconnection. The Luer connector 135 shown is a Luer-Lok type connectorcomprising screw threads. However, the Luer connector can also be aLuer-slip type connector without screw threads. In some embodiments, thedistal end 133 of the cap 130 includes an annular channel thatreleasably attaches to the VAD and the proximal end 132 has an annularchannel that releasably attaches the cap 130 to the barrel 110. Eitherof the annular channels can include at least one screw thread adapted toallow the cap to be screwed onto one or more of the barrel 110 and theVAD. In some embodiments, the cap can engage complementary threads onthe VAD or engages the VAD with an interference fit.

Additionally, the proximal end 132 of the cap 130, as shown in FIGS. 4Band 5, is releasably attachable to the barrel 110 via a suitableconnector 137. Suitable connectors 137 include, but are not limited to,Luer slip and Luer-Lok type connectors. FIG. 4B shows the proximal end132 of a cap 130 in accordance some embodiments. The connector 137 shownin FIG. 4B is a Luer-Lok type connector which includes screw threads.

The passageway 134 can be smooth, rough, coated or uncoated. In someembodiments the inner surface of the passageway 134 is coated with anantimicrobial agent.

In some embodiments, the cap 130 includes a distal end annular channel231 comprising a straight inner wall 232 and an outer wall 233 that isthreaded to complement threads on the VAD or form an interference fit.The distal end annular channel 231 can extend less than the length ofthe cap 130. For example, the distal end annular channel 231 can extendless than about 90% of the length of the cap 130, or less than about 80%of the length of the cap 130, or less than about 70% of the length ofthe cap 130, or less than about 60% of the length of the cap 130, orless than about 50% of the length of the cap 130.

In some embodiments, the cap 130 includes a proximal end annular channel235 which comprises a straight outer wall 236 and an inner wall 237 thatis releasably attached to the barrel 110. The proximal end annularchannel 235 can extend less than the length of the cap 130. For example,the proximal end annular channel 235 can extend less than about 90% ofthe length of the cap 130, or less than about 80% of the length of thecap 130, or less than about 70% of the length of the cap 130, or lessthan about 60% of the length of the cap 130, or less than about 50% ofthe length of the cap 130. The proximal end annular channel 235 can beconnected to the barrel by one or more of threaded connections or by aninterference fit.

In some embodiments, the flush syringe 100 includes a sleeve 160 and adisinfecting system 170. As shown in FIGS. 1 and 6 to 7, the sleeve 160is coaxial with and external to the barrel 110 and has a proximal end161, a distal end 162, an inside surface 163 and an outside surface 164.The sleeve 160 can slide from a distal position to a proximal positionrelative to the barrel 110. The sleeve of some embodiments covers thecap 130 prior to use of the flush syringe assembly 100. The sleeve 160may include a cavity 166 on the distal end 162 that is sized to enclosethe cap 130. The flush syringe assembly 100 can be packaged with thesleeve 160 already in place or as a separate component. The sleeve canbe used to disengage the disinfectant carrier 175, described below,and/or cover the cap 130 until flushing of the vascular access deviceconnection is complete.

The shape of the sleeve 160 can vary depending on the use of the device.For example, as shown in the drawings, the sleeve 160 is round, like thebarrel 110, and sized to fit around the barrel 110. The sleeve 160 hasone or more cutouts 165 which allow visibility of the barrel 110 and thecontents therein. The sleeve can have any number of cutouts 165including, but not limited to, one, two, three and four cutouts. Forexample, the sleeve 160 shown in the Figures has two cutouts 165 onopposite sides of the sleeve 160. Without being bound by any particulartheory of operation, it is believed that the cutouts provide greatervisibility of the contents of the barrel and/or increase the flexibilityof the sleeve to allow the sleeve to more easily conform to the outsidesurface of the barrel and/or to facilitate motion of the barrel relativeto the sleeve.

The distal end 162 of the sleeve 160, in some embodiments, has athreaded portion 169 which can be used to attach the disinfecting system170. While a threaded portion 169 is shown, it will be understood bythose skilled in the art that other attachment mechanisms can be usedincluding, but not limited to, interference fits.

In some embodiments, the inside surface 163 of the sleeve 160 comprisesone or more grooves 177 that engage with corresponding ridge (or ridges)138 on the outside surface of the barrel 110 to facilitate alignment ofthe barrel and sleeve while the plunger is depressed. In one or moreembodiments, the plunger is of sufficient length relative to the sleeveand the barrel so that when the plunger is fully depressed, afterflushing solution has been pushed through the VAD, the sleeve retracts,thereby exposing the cap.

In some embodiments, the sleeve is external to the barrel 110 and has anopen proximal end 161 containing at least one flange 173 and an opendistal end 162 defining a recess 166 with an inner surface to containthe cap. In detailed embodiments the recess 166 is irregularly shaped toprevent rotation of the cap relative to the sleeve. For example, therecess 166 may have a hexagonal shape matching a hexagonal shaped cap.

In one or more embodiments, the sleeve 160 comprises two linear grooves177 positioned on opposite sides (about 180° apart) that runsubstantially from the proximal end of the sleeve toward the distal endof the sleeve. The linear grooves 177 can be configured to interact withthe ridges 138 on the outside surface of the barrel 110.

Referring to FIG. 1, the disinfecting system 170 comprises adisinfectant on a disinfectant carrier 175 contained in a hub 180. Thehub 180 has a proximal face 181 and a distal face 182 and is sized tofit within the cover 185. The hub 180 can be made from any suitablematerial including, for example, a thermoplastic material. The distalface 182 of the hub 180 can be substantially flat or have a recessedsection.

The disinfectant carrier 175 can be any suitable material capable ofcarrying and providing a disinfecting medium to the vascular accessdevice. The disinfectant carrier 175 can be adhered to the distal face182 of the hub 180 by any suitable means including, but not limited to,medical grade adhesive or tape. In one or more embodiments, thedisinfectant carrier 175 is sized to fit within a recess in the distalface 182 of the hub 180 and can be secured thereto by either adhesive orby an interference fit.

The disinfectant can be any suitable composition capable of cleaning theconnection to the vascular access device. In one or more embodiments,the disinfectant carrier 175 is saturated with, or wetted with, asolution comprising the disinfectant. In some embodiments, thedisinfectant comprises one or more disinfecting materials such asalcohol and antiseptic gels. The disinfectant carrier 175 of someembodiments includes sufficient disinfectant to disinfect the VAD'sinlet port.

In some embodiments, the disinfecting system 170 further comprises aremovable cover 185. The removable cover 185 is capable of protectingthe disinfecting system prior to use including the disinfectant carrier175. The removable cover 185 can be connected to either the hub 180 withthe sleeve 160 by one or more of an interference fit or throughengagement of complement retreads.

The disinfecting system 170 can be assembled on the distal end of theflush syringe assembly 100 in a number of configurations. In one or moreembodiments, the disinfecting system 170 is arranged such that thedisinfectant carrier 175 is fitted within a recess on the distal face182 of the hub 180. The proximal face 181 of the hub 180 is positionedadjacent the distal end 133 of the cap 130 and is held in place byengagement with the inside surface of the distal end 162 of the sleeve160 by either complementary screw threads or an interference fit. Thecover 185 is positioned over the disinfectant carrier 175 and the hub180 and is attached to the distal end 162 of the sleeve 160 by one ormore of complement or the screw threads or interference fit. In one ormore embodiments, the disinfecting system 170 is attached to the distalend 162 of the sleeve 160 by an interference fit. In some embodiments,the disinfecting system 170 is attached to the distal end 162 of thesleeve 160 by engagement of complementary threads.

In one or more embodiments, the outside surface 113 of the barrel 110includes a least one annular ridge 167, as shown in FIGS. 1 and 2. Theannular ridge 167 is sized to provide a hindrance to spontaneousmovement of the sleeve 160 relative to the barrel 110. The hindrance canbe provided by, for example, an interference fit or cooperativeinteraction between a complementary feature 171 on the inside surface163 of the sleeve 160. In some embodiments, the outside surface 113 ofthe barrel 110 includes at least two annular ridges 167, 168, as shownin FIGS. 1 through 8. Referring to FIG. 1, the annular positioningridges comprise a distal annular positioning ridge 167 and a proximalannular positioning ridge 168. Also shown in FIG. 1, the sleeve 160includes at least one annular positioning groove 171. In FIGS. 6-7, thesleeve 160 includes at least two annular positioning grooves: a distalannular positioning groove 171 and a proximal positioning groove 172.The annular positioning grooves 171, 172 are sized and positioned tohelp control the position of the sleeve 160 relative to the barrel 110by engaging with the at least one annular positioning ridge 167, 168 onthe outside surface 113 of the barrel 110.

In some embodiments, the sleeve 160 further comprises at least oneflange 173 adjacent the proximal end 161 of the sleeve 160. The at leastone flange 173 provides a region that can be gripped by the user to aidein the movement of the sleeve 160 relative to the barrel 110.

Some embodiments of the flush syringe assembly 100 further comprise agasket 190. The gasket 190 can be sized to fit around the distalportion, including the tip 119, of the barrel 110 between the cap 130and the distal wall 117 of the barrel 110. The gasket 190 can be made ofany suitable material including, but not limited to, resilient rubber orplastic. The gasket 190 helps form a seal between the barrel 110 and thesleeve 160 and may have an outer diameter substantially equal to theouter diameter of the barrel 110 at the annular positioning ridges 167,168. In some embodiments, there is an interference fit between thebarrel 110 and the sleeve 160 without the need for a gasket 190.

The operation of a syringe assembly in accordance with one or moreembodiments of the invention is now described with respect to FIGS. 12through 32. FIGS. 12 to 13 show an embodiment of the flush syringeassembly 100 in initial state. The plunger rod 120 is positioned suchthat the stopper 150 is adjacent the proximal end 115 of the barrel 110.In this position, the chamber 114 has a maximum effective volume and canbe either full of a medicament or empty. It will be understood by thoseskilled in the art that the flush syringe assembly 100 can be operatedin the opposite fashion whereby in the initial state, the plunger rod120 is positioned in the distal most position so that the cavity volumeis minimized. Additionally, the plunger rod 120 can be initiallypositioned at any point between the proximal most position and thedistal most position allowing for various uses and volumes of prefilledmedicaments.

In the initial state, the disinfecting system 170 is connected to thedistal end 162 of the sleeve 160 so that the hub 180 is connected to thesleeve with the disinfectant carrier 175 is positioned distally of thehub 180 and the cover 185 covers both the hub 180 and the disinfectantcarrier 175. While other connections types can be used, the embodimentshown in the figures has the disinfecting system 170 connected to thesleeve 160 by cooperative interaction of screw threads on the outside ofthe sleeve 160 and the inside surface of the hub 180.

As shown in FIGS. 14 and 15, removal of the cover 185 exposes thedisinfectant carrier 175 for use. The hub 180 and the distal face 182 ofthe hub 180 can be seen protruding slightly from the distal end 162 ofthe sleeve 160. With the disinfectant carrier 175 exposed, as shown inFIGS. 16 and 17, the user can clean the connection to the vascularaccess device 199 by contacting the disinfectant carrier 175 to the VAD199.

Referring to FIGS. 18 and 19, after cleaning the vascular access device199, the user applies proximally directed force on the sleeve 160relative to the barrel 110. The proximally directed force can be appliedto the sleeve 160 with the aide of the flange 173 on the sleeve 160.This proximally directed force causes the sleeve 160 to slide proximallyrelative to the barrel 110 so that the sleeve slides from the distalposition where the distal positioning ridge 167 is located to theproximal position where the proximal positioning ridge 168 is located.Proximal movement of the sleeve 160 relative to the barrel 110 isequivalent to distal movement of the barrel 110 relative to the sleeve160. This distal movement of the barrel 110 relative to the sleevecauses the tip 136 of the cap 130 to press against the proximal face 181of the hub 180, forcing the hub 180 to become disengaged from the distalend 162 of the sleeve 160. In the embodiment shown, the hub 180 isconnected to distal end 162 of the sleeve 160 by an interference fit sothat distally directed pressure on the hub 180 can cause the hub 180 topushed out of the sleeve 160 without requiring a twisting motion. FIG.19 shows the flush syringe assembly 100 after cleaning the vascularaccess device 199 and disengagement of the hub 180. The distal end ofthe cap 130 can be seen extending from the distal end 162 of the sleeve160. FIG. 20 shows the proximal end of the barrel and sleeve with thesleeve 160 in the proximal position resting against stops 188 on theoutside surface of the barrel. The stops 188 provide additionalinterference to prevent the sleeve from moving too far along the lengthof the barrel, thereby becoming disengaged from the barrel.

After the disinfecting system 170 has been removed from the distal endof the syringe assembly, the vascular access device 199, which is nowclean, can be attached to the distal end 133 of the cap 130. FIGS. 21 to23 show the flush syringe assembly after removal of the disinfectingsystem 170 and attachment of the VAD 199 to the cap 130. In FIG. 24, thestopper 150 and plunger rod 120 are shown at a point midway along thelength of the barrel 110. This is representative of a flush syringeassembly in which part of the medicament or solution within the chamber114 has been expelled through the cap 130 into the vascular accessdevice 199.

FIGS. 25 and 26 show the plunger rod 120 and stopper 150 in the distalmost position. Here, the distal end of the detachable stopper tip 155has been forced into the undercut region 192 of the cap 130. FIGS. 27and 28 show the sleeve 160 after proximal movement to expose the capfrom the distal end of the sleeve. FIG. 29 shows the proximal end of thesleeve 160, barrel 110 and plunger rod 120 after the proximal movementto expose the cap 130.

After the flush syringe is used, and the detachable stopper tip 155 hasbeen forced into the undercut region 192 of the cap 130, the 130 andstopper tip 155 can be released from the distal end of the barrel 110and left attached to the vascular access device 199, as shown in FIGS.30 to 32. This is effective to cap off the vascular access device 199 toprevent contamination and minimize the need for future cleaning. Cappingthe VAD 199 also helps prevent blood refluxing through the VAD 199.

Additional embodiments of the invention are directed to methods offlushing a VAD. A flush syringe assembly, as described herein, isprovided along with instructions regarding the proper operation of theflush syringe assembly. The flush syringe assembly is then usedaccording the provided instructions.

Further embodiments of the invention are directed to methods of flushinga VAD comprising providing or receiving the flush syringe assemblydescribed herein. One hand is used to remove the protective cover 185from the distal end of the flush syringe assembly thereby exposing adisinfectant carrier 175 carrying a disinfectant. One hand is used toapply the disinfectant to the VAD connecter. The same hand is used toeject the disinfecting system 170 from the distal end of the syringeassembly. The flush syringe assembly is coupled to the VAD. One hand isused to hold the flush syringe assembly and depress the plunger to flushthe VAD with a flush solution that is contained within the syringebarrel (either prefilled or not prefilled). Using the same hand, theplunger rod is continued to be depressed after the barrel is empty toembed the stopper tip into the VAD and retract the sleeve to expose thecap 130. The cap including the embedded stopper tip is separated fromthe flush syringe assembly. In some embodiments, the cap with theembedded stopper tip can be removed from the VAD and the process can berepeated with another flush syringe assembly.

What is claimed is:
 1. A flush syringe assembly comprising: a barrelincluding a side wall having an inside surface defining a chamber forretaining fluid, an outside surface, an open proximal end, a distal endincluding a distal wall with a tip extending distally therefrom having apassageway therethrough in fluid communication with the chamber, thebarrel further comprising an outside surface having one or more annularpositioning discontinuity; a cap comprising a distal end and a proximalend defining a length, an irregularly shaped outer wall, a profiledcenter passageway providing fluid communication from the chamber to apatient's vascular access device (VAD), further comprising a distal endannular channel that releasably attaches the cap to the VAD, and aproximal end annular channel that releasably attaches the cap to thebarrel; a releasable disinfecting system comprising a disinfectant; anelongate plunger rod disposed within the barrel, the plunger rodcomprising a distal portion and a proximal portion, the plunger rodfurther comprising a distal end including a stopper slidably positionedin fluid-tight contact with the inside surface of the barrel forexpelling fluid from the chamber by movement of the stopper relative tothe barrel, the stopper having a distal face and a proximal end, thedistal face of the stopper further comprising a profiled stopper tipthat is detachable from the stopper and seatable in the cap when theplunger rod is fully depressed; and a sleeve external to the barrelhaving an inside surface and an outside surface, an open proximal endcontaining at least one flange, and an open distal end defining a recesswith an irregular inner surface to contain and prevent rotation of thecap relative to the sleeve, the distal end further connected to thereleasable disinfecting system, the sleeve further comprising one ormore annular positioning discontinuity complementary to the one or moreannular positioning discontinuity on the barrel which together controldistal motion of the barrel relative to the sleeve.
 2. The flush syringeassembly of claim 1, wherein the distal end annular channel of the capfurther comprises a straight inner wall and an outer wall that isthreaded to complement the VAD, and the distal end annular channelextends less than the length of the cap.
 3. The flush syringe assemblyof claim 1, wherein the proximal end annular channel of the cap furthercomprises a straight outer wall and an inner wall that is releasablyattached to the barrel, and the proximal end annular channel extendsless than the length of the cap.
 4. The flush syringe assembly of claim1, wherein the proximal end annular channel of the cap is attached tothe barrel by one or more of an interference fit and a threadedconnector.
 5. The flush syringe assembly of claim 1, wherein theprofiled center passageway of the cap extends the entire length of thecap to establish fluid connection between the barrel and the VAD, andthe profile of the center passageway is undercut near the proximal endto complement the profile of an external surface of stopper tip.
 6. Theflush syringe assembly of claim 5, wherein the profiled centerpassageway of the cap is coated with an antimicrobial agent.
 7. Theflush syringe assembly of claim 1, wherein the stopper or any portion ofthe stopper is detachable and capable of being embedded into the VAD. 8.The flush syringe assembly of claim 1, wherein the stopper has a cavityto hold a stopper tip by one or more of a threaded connection and aninterference fit.
 9. The flush syringe assembly of claim 1, wherein theprofile of the distal end of the stopper tip is configured to complementthe profile of the center passageway of the cap and create aninterference fit therewith sufficient to retain the stopper tip withinthe VAD after the flush syringe assembly is removed.
 10. The flushsyringe assembly of claim 1, wherein stopper tip is threadably attachedto stopper using threads on the stopper tip that complement those on theVAD allowing both to be removed in one motion by the practitioner. 11.The flush syringe assembly of claim 1, wherein the annular positioningdiscontinuities on the barrel comprise two annular positioning ridges: adistal annular positioning ridge and a proximal annular positioningridge and the discontinuity on the sleeve comprises a groove configuredto interact with the annular positioning ridges on the barrel.
 12. Theflush syringe assembly of claim 1, wherein the outside surface of thebarrel further comprises one or more linear discontinuity spaced aroundthe barrel that run along a length of the barrel and engage with acorresponding discontinuity on the inside surface of the sleeve.
 13. Theflush syringe assembly of claim 1, further comprising a quantity offlush solution in the chamber between the stopper and distal wall of thebarrel.
 14. The flush syringe assembly of claim 1, wherein the stopperbody and stopper tip are independently made of a material selected fromthe group consisting of thermoplastic elastomers, natural rubber,synthetic rubber, thermoplastic materials and combinations thereof. 15.The flush syringe assembly of claim 1, wherein the sleeve furthercomprises one or more cutouts to provide visibility to contents of thebarrel.
 16. The flush syringe assembly of claim 1, wherein the plungeris of sufficient length relative to the sleeve and the barrel that whenplunger is fully depressed after all flushing solution has been expelledfrom the syringe, the sleeve retracts to expose the cap.
 17. The flushsyringe assembly of claim 1, wherein the distal end of the sleeve isthreaded to engage complementary threads on the disinfecting system. 18.The flush syringe assembly of claim 1, wherein the distal end of thesleeve is attached to the disinfecting system using an interference fit.19. The flush syringe assembly of claim 1, wherein the disinfectingsystem further comprises a removable cover to protect the disinfectingsystem prior to use and a disinfectant carrier.
 20. The flush syringeassembly of claim 1, wherein the disinfectant is made of materialselected from the group consisting of: an alcohol, an antiseptic gel,and combinations thereof.
 21. The flush syringe assembly of claim 1,wherein the barrel does not include a flange for providing opposingforce to the direction of movement of an elongate plunger rod.
 22. Theflush syringe assembly of claim 1, wherein the sleeve slidably engagesthe barrel from a distal position to a proximal position, and the flangeis effective to provide a region that can be gripped by the user to aidein the movement of the sleeve relative to the barrel.